Recent Advances in MST and EISCAT/Ionospheric Studies– Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017

Editorial Board (August 2021)
Editor-in-Chief
Takeshi Sagiya, Nagoya University, Japan

Vice Editors-in-Chief
Masahito Nosé, Nagoya University, Japan

Aitaro Kato, University of Tokyo, Japan

Editors
Hideo Aochi
Pascal Audet
Kiyoshi Baba
Joseph B.H. Baker
Nanan Balan
Stephan Christoph Buchert
Sonia CalvariPeter Chi
Harold C. Connolly Jr
Phil Cummins
Hao Dong
Guangyu Fu
Hidenori Genda
Aditya Gusman
Tomasz Hadaś
Shin-Chan Han
Stuart Henrys
James Hickey
Hauke Hussmann

Mie Ichihara
Takeo Ito
Hidekatsu Jin
Art Jolly
Shunichi Kamata
Nobuki Kame
Yoko Kebukawa
Kunihiro Keika
Tomokazu Kobayashi
Kostas Konstantinou
Alexey Kuvshinov
Juanjo Ledo
Atsuko Namiki
Yasuhito Narita
Kazunari Nawa
Hiroyo Ohya
Duggirala Pallamraju
Severine Rosat
Akinori Saito

Tatsuhiko Saito
David Shelly
Hisayoshi Shimizu
Hiroko Sugioka
Wataru Suzuki
Youichiro Takada
Sunny Tam
Naoki Uchida
Yanbin Wang
Yih-Min Wu
Chuang Xuan
Takahiro Yamamoto
Yuhji Yamamoto
Tadashi Yamasaki
Tatsuhiro Yokoyama
Kazunori Yoshizawa
Yohei Yukutake
Seiji Zenitani

Hiroo Kanamori
Jun'ichiro Kawaguchi
Takafumi Matsui
Hitoshi Mizutani

Yasuo Ogawa
Toshitaka Tsuda
Zhongliang Wu
Kiyoshi Yomogida

Advisory Board
Benjamin Fong Chao
Bernard Chouet
Yoshimori Honkura
Toshihiko Iyemori

Journal Scope
Earth, Planets and Space (EPS) is the official journal of Society of Geomagnetism and Earth, Planetary
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Geodetic Society of Japan, and The Japanese Society for Planetary Sciences.
EPS is a peer-reviewed, open-access journal published under SpringerOpen. It is an international journal
covering scientific articles in the entire field of earth and planetary sciences, particularly geomagnetism,aeronomy, space science, seismology, volcanology, geodesy, and planetary science. EPS also welcomesarticles in new and interdisciplinary subjects, and technical reports on instrumentation and software.
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Earth, Planets and Space(2019) 71:99
Yamamoto et al. Earth, Planets and Space
https://doi.org/10.1186/s40623-019-1070-2

Open Access

PREFACESpecial issue “Recent Advances in MST
and EISCAT/Ionospheric Studies – Special Issueof the Joint MST15 and EISCAT18 Meetings, May
2017”
Mamoru Yamamoto1* , Wayne K. Hocking2, Satonori Nozawa3, Juha Vierinen4, Huixin Liu5
and Nozomu Nishitani3

Introduction
The Fifteenth Workshop on Technical and Scientific
Aspects of MST Radar (MST15) and the Eighteenth EISCAT Symposium (EISCAT18) were jointly held in Tokyo,
Japan, at the National Institute of Polar Research (NIPR)
during May 26–31, 2017. The MST workshops have along history of being the primary international meetings
on the applications and development of mesosphere–
stratosphere–troposphere (MST) radars. The MST
workshop has been historically focusing on the atmospheric dynamics but is now including topics related toionospheric applications of radars. The EISCAT Symposium, on the other hand, is the biennial conference
for EISCAT-related radar research and science which ishosted by member institutions of the EISCAT Scientific
Association.
This joint MST15/EISCAT18 meeting was a timely
opportunity for close and extensive interactions of the
middle-atmosphere and ionospheric radar scientists in
our era of rapid technological changes and computational
advances. The joint meeting was successfully attended by
182 participants from 19 countries/areas and hosted 233
presentations. These numbers were the maximum levelever for either conferences.
This special issue gathered 15 papers from this joint
meeting, consisting of ten full papers, three frontier/express letters and two technical reports. The flexible
publication style of Earth, Planets and Space benefitted
us to cover easily both scientific and technical aspects of
the research field. In the following, we categorize the articles into several groups and review them briefly.

Contents of the special issue
Study of atmospheric turbulence

One of important topics of the MST radars is atmospheric turbulence. In this special issue, there are threepapers from the same research group who conductedjoint experiment of the atmospheric turbulence byremote sensing with the MU radar and by direct measurement with an unmanned aerial vehicle (UAV) thatflew nearby to the radar. Luce et al. (2018a) showed acase study of Kelvin–Helmholtz instability (KHI) at thebottom of clouds. The KHI billow structures were successfully observed by the MU radar while a fish-eyelens camera on the ground captured the same event.
The authors suggested that this is the first simultaneous
detection of KHI from ground-based camera and a radar.
Luce et al. (2018b) is the study of concurrent measurement of atmospheric turbulence by the MU radar anda UAV. The UAV measured turbulence kinetic energy(TKE) dissipation rate (εU ) by a low-noise Pitot tube, andthe MU radar showed turbulence intensity by the spectral width (σ ). The paper first confirmed same-volume
observation by both techniques, and statistically studied empirical relationship between εU and σ . The resultis εU ∝ σ 3 that is different from previously expectedεU ∝ σ 2 relationship. Kantha et al. (2018) conducted*Correspondence: yamamoto@rish.kyoto‑u.ac.jp
1
Research Institute for Sustainable Humanosphere (RISH), Kyoto
University, Gokasho, Uji, Kyoto 611‑0011, Japan
Full list of author information is available at the end of the article© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

1

Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017
Yamamoto et al. Earth, Planets and Space(2019) 71:99

Page 2 of 3

from multistatic meteor radar observations. The network of several meteor radars benefits us to diagnosehorizontal wind field over the network. This paper points
out possible error from such simultaneous measurementof winds from different locations and proposes software
to show the error estimation. Reid et al. (2018b) carriedout wind comparisons between meteor radars and MF
radars at middle- and high-latitude regions in the southern hemisphere. They showed that the winds from MF
radars are underestimated and the problem is enhanced
above 80 km. They suggested correction factors to mitigate the problem. Renkwitz et al. (2018) carried out windcomparison study between different wind estimation
techniques. The study is based on the Saura MF radar(69.1°N, 16.0°E) that is an MF radar but can conduct the
Doppler beam swinging (DBS) wind estimation with narrow beams. They showed that the wind estimation suffersfrom underestimation and suggested optimum combination of methods for better estimation of winds.

further study of this εU and σ relationship based on thesame database as Luce et al. (2018b). They discussed thevalidity of the previous theoretical expression of the εUand σ relationship. After pointing out missing considerations in the past theories, they proposed a new numericalmodel described as a MATLAB code for later practicaluse by the radar community.
Study of polar mesospheric echoes

There are three papers on the study of polar mesosphericechoes. Rauf et al. (2018) conducted a statistical studyof influence of particle precipitation on the polar mesospheric summer echoes (PMSE) with the EISCAT VHF
radar. They showed that particle precipitation is not anecessary condition for PMSE to exist. However, particle precipitation still affects PMSE when they both occur
simultaneously. Reid et al. (2018a) used PMSE echo data
for the measurement of momentum flux and found reasonable results compared to previous studies with meteor
radars and medium frequency (MF) radars. Belova et al.
(2018) conducted a case study of polar mesospheric winter echoes (PMWE) using the tristatic EISCAT radar.
Echo duration of the measured PMWE was only 6 min.
Then, they found that the presence of patchy negatively
charged small-sized dust might explain the observations.

New observations and survey for new experiment

It is important to explore new observation methods inany research fields. There are three papers (one frontier
letter and two technical reports) in this category. Satoet al. (2018) reported measurement of horizontal structures of the ionosphere from Synthetic Aperture Radar(SAR) measurement aboard the Advanced Land Observation Satellite 2 (ALOS2). This is a very interesting
method as the information of azimuth shifts of the SAR
image is used for the measurement of horizontal gradient of ionospheric plasma density. They used the EISCAT radar as a reference of observations. There are twomore technical reports by Tsuda et al. (2018a, b). They
surveyed conditions for artificial aurora experiment with
ionospheric heating facility and the IS radar at EISCAT
Tromsø site. One report (Tsuda et al. 2018a) suggests thecase where they use 4 MHz radio wave for ionosphericheating. However, the chances of possible observations are not high and mostly hopeless during the solar
minimum period. In the following report (Tsuda et al.
2018b), they surveyed the possibility of artificial aurora
experiment if they can use 2.7 MHz radio wave for heating. They suggested that, by decreasing the frequency ofthe heating radio wave from 4 to 2.7 MHz, the chance ofexperiment is much larger and becomes possible evenduring the solar minimum period.

Introduction of new radar facilities

Development of new radar facilities is important for the
research field. There are three papers in this category.
Ding et al. (2018) showed a newly developed incoherent
scatter (IS) radar in Qujing, China (25.6°N, 103.8°E). Thisis the first IS radar in China that operates at 500 MHz
with 2 MW peak envelope power (PEP). The antenna system is 29-m steerable parabolic dish. System description
and some preliminary results are reported. Dolman et al.
(2018), on the other hand, reported installation of windprofiling radar network over Australian continent. Australian Government Bureau of Meteorology added five
more radars. Then, the network now consists of 19 radars(14 operational radars and 5 radars for research). Wind
data are included in major models and contribute to moreaccurate weather forecast. Another paper by GarbanzoSalas and Hocking (2019) reported a study on 1-year datafrom the first VHF wind profiler radar in Costa Rica. The
radar frequency is 46.6 MHz, and measures wind profiles
in the height range of 1–6 km with height resolution of
100 m. They successfully showed behavior of the planetary boundary layer in the low-latitude region.

Acknowledgements
We thank all participants of the Joint MST15/EISCAT18 Meeting in May 2017and give special acknowledgement to all authors in our special issue. We
highly appreciate all referees who served in evaluating the papers and giving
the authors helpful comments and suggestions.

Study of radar measurement techniques

The accuracy in wind estimation is a very important
technical topic for the radar. There are three papers
related to this. Hocking (2018) studied possible error

2Earth, Planets and Space
Yamamoto et al. Earth, Planets and Space(2019) 71:99

Page 3 of 3

Authors’ contributions
All authors of this article worked as guest editors for this special issue. Four ofthem (MY, WKH, SN, and JV) were the conveners of the Joint MST15/EISCAT18
Meeting as well. This preface was prepared by MY and agreed upon by all
authors. All authors read and approved the final manuscript.

Hocking WK (2018) Spatial distribution of errors associated with multistatic
meteor radar. Earth Planets Space 70:93. https://doi.org/10.1186/s4062
3‑018‑0860‑2
Kantha L, Luce H, Hashiguchi H (2018) On a numerical model for extracting
TKE dissipation rate from very high frequency (VHF) radar spectral width.
Earth Planets Space 70:205. https://doi.org/10.1186/s40623‑018‑0957‑7
Luce H, Kantha L, Yabuki M, Hashiguchi H (2018a) Atmospheric Kelvin‑
Helmholtz billows captured by the MU radar, lidars and a fish‑eye camera.
Earth Planets Space 70:162. https://doi.org/10.1186/s40623‑018‑0935‑0
Luce H, Kantha L, Hashiguchi H, Lawrence D, Doddi A (2018b) Turbulencekinetic energy dissipation rates estimated from concurrent UAV and MU
radar measurements. Earth Planets Space 70:207. https://doi.org/10.1186/
s40623‑018‑0979‑1
Rauf A, Li H, Ullah S, Meng L, Wang B, Wang M (2018) Statistical study about
the influence of particle precipitation on mesosphere summer echoes inpolar latitudes during July 2013. Earth Planets Space 70:108. https://doi.
org/10.1186/s40623‑018‑0885‑6
Reid IM, Rüster R, Czechowsky P, Spargo AJ (2018a) VHF radar measurements
of momentum flux using summer polar mesopause echoes. Earth Planets
Space 70:129. https://doi.org/10.1186/s40623‑018‑0902‑9
Reid IM, McIntosh DL, Murphy DJ, Vincent RA (2018b) Mesospheric radar windcomparisons at high and middle southern latitudes. Earth Planets Space
70:84. https://doi.org/10.1186/s40623‑018‑0861‑1
Renkwitz T, Tsutsumi M, Laskar FI, Chau JL, Latteck R (2018) On the role of ani‑sotropic MF/HF scattering in mesospheric wind estimation. Earth Planets
Space 70:158. https://doi.org/10.1186/s40623‑018‑0927‑0
Sato H, Kim JS, Jakowski N, Häggström I (2018) Imaging high‑latitude plasma
density irregularities resulting from particle precipitation: spaceborne
L‑band SAR and EISCAT observations. Earth Planets Space 70:163. https://doi.org/10.1186/s40623‑018‑0934‑1
Tsuda TT, Rietveld MT, Kosch MJ, Oyama S, Hosokawa K, Nozawa S, Kawabata
T, Mizuno A, Ogawa Y (2018a) Survey of conditions for artificial aurora
experiments at EISCAT Tromsø using dynasonde data. Earth Planets
Space 70:40. https://doi.org/10.1186/s40623‑018‑0805‑9Tsuda TT, Rietveld MT, Kosch MJ, Oyama S, Ogawa Y, Hosokawa K, Nozawa
S, Kawabata T, Mizuno A (2018b) Survey of conditions for artificial
aurora experiments by the second electron gyro‑harmonic at EISCAT
Tromsø using dynasonde data. Earth Planets Space 70:94. https://doi.
org/10.1186/s40623‑018‑0864‑y

Ethics approval and consent to participate
Not applicable.
Consent for publication
Not applicable.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Research Institute for Sustainable Humanosphere (RISH), Kyoto University,
Gokasho, Uji, Kyoto 611‑0011, Japan. 2 Department of Physics and Astronomy,
University of Western Ontario, 1151 Richmond St. North, London, ON N6A 3K7,
Canada. 3 Institute for Space‑Earth Environmental Research, Nagoya University,
Furo‑cho, Chikusa‑ku, Nagoya 464‑8601, Japan. 4 Department of Physics
and Technology, University of Tromsø, The Arctic University of Norway, Han‑sine Hansens Veg 18, 9037 Tromsø, Norway. 5 Department of Earth and Plan‑
etary Sciences, Graduate School of Sciences, Kyushu University, 744 Motooka,
Nishi‑ku, Fukuoka 819‑0395, Japan.
Received: 10 August 2019 Accepted: 13 August 2019

References
Belova E, Kawnine M, Häggström I, Sergienko T, Kirkwood S, Tjulin A (2018)
Tristatic observation of polar mesosphere winter echoes with the EISCATVHF radar on 8 January 2014: a case study. Earth Planets Space 70:110.
https://doi.org/10.1186/s40623‑018‑0878‑5
Ding Z, Wu J, Xu Z, Xu B, Dai L (2018) The Qujing incoherent scatter radar:system description and preliminary measurements. Earth Planets Space
70:87. https://doi.org/10.1186/s40623‑018‑0859‑8
Dolman BK, Reid IM, Tingwell C (2018) Stratospheric tropospheric wind profil‑
ing radars in the Australian network. Earth Planets Space 70:170. https://doi.org/10.1186/s40623‑018‑0944‑z
Garbanzo‑Salas M, Hocking W (2019) Characterization of atmospheric struc‑tures observed by a VHF MST‑type radar in the troposphere over Santa
Cruz, Costa Rica. Earth Planets Space 71:6. https://doi.org/10.1186/s4062
3‑019‑0985‑yPublisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims in pub‑lished maps and institutional affiliations.

3

Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017

FRONTIER LETTER

Open Access

Imaging high-latitude plasma density irregularities resulting
from particle precipitation: spaceborne L-band SAR and
EISCAT observations
Hiroatsu Sato*, Jun Su Kim, Norbert Jakowski and Ingemar Häggström
Earth, Planets and Space 2018, 70, 163 DOI: 10.1186/s40623-018-0934-1
Received: 2 March 2018, Accepted: 26 September 2018, Published: 4 October 2018

Abstract
High-latitude, small-scale plasma density irregularities are observed by the Advanced Land Observation Satellite 2, Phase
Array type L-band Synthetic Aperture Radar-2 and the European Incoherent Scatter radar in Tromsø, Norway. Under highlevels of ionization of up to approximately 300 km in height triggered by nighttime particle precipitation, high-resolution SAR
images detect horizontal distributions of azimuth shifts resulting from the spatial gradients of electron density. The irregularelectron density is characterized by tens of kilometers of band-like structures aligned in the east–west direction with small
patch-like structures. We present a method for estimating
the local change of TEC gradient and the height ofionospheric irregularities by using single-image SAR
sub-band data. The results suggest that these observed
structures are likely to be associated with density
irregularities caused by precipitating electrons that may
have been cascaded into smaller scales by plasma
instability processes at F region altitudes. This study
presents the first coordinated observations of highlatitude ionosphere features by using SAR satellites andincoherent scatter radar.

Keywords: Ionosphere, High latitudes, TEC, SAR, EISCAT

Graphical abstract*Corresponding author: Hiroatsu Sato, hiroatsu.sato@dlr.de

FRONTIER LETTER

Open Access

Characterization of atmospheric structures observed by
a VHF MST-type radar in the troposphere over Santa Cruz,
Costa Rica
Marcial Garbanzo-Salas* and Wayne Hocking
Earth, Planets and Space 2019, 71, 6 DOI: 10.1186/s40623-019-0985-y
Received: 28 February 2018, Accepted: 4 January 2019, Published: 15 January 2019

Abstract
Results from the first VHF profiler research radar in Costa Rica, operating at a central radar frequency of 46.6 MHz, are presented.
Emphasis has been on studies of scattering layers detected in the altitude range 1–6 km, with the main goal being to identify
regions with radar echoes and observe the temporal evolution of the echoes. Data were obtained over the course of a full year
using a vertical resolution of better than 100 m. Layers of strong scatter were observed regularly, often with simultaneous broad
spectra, which may indicate enhanced turbulence. Similar layers have been observed over equatorial Indonesia, and these havebeen associated with the planetary boundary layer. The presence of echo layers was more common during the dry-season
months (December–April); in fact during March, two layers were observed in the lower troposphere for more than 35% of thetime. Stable pattern structures often
occurred for extended periods, but at times
the layers could also vary drastically inbehavior from 1 day to the next. Aftersunset, strong echo layers could persist forseveral hours. Some examples of regularly
observed layer behavior are given.

Keywords: MST type radar, Planetary
boundary layer, Layers of
turbulence

Graphical abstract*Corresponding author: Marcial Garbanzo-Salas, marcial.garbanzo@ucr.ac.cr
4

Earth, Planets and Space

FULL PAPER

Open AccessMesospheric radar wind comparisons at high andmiddle southern latitudes
Iain M. Reid*, Daniel L. McIntosh, Damian J. Murphy and Robert A. Vincent
Earth, Planets and Space 2018, 70, 84 DOI: 10.1186/s40623-018-0861-1
Received: 22 February 2018, Accepted: 15 May 2018, Published: 21 May 2018

Abstract
We compare hourly averaged neutral winds derived from two meteor
radars operating at 33.2 and 55 MHz to estimate the errors in thesemeasurements. We then compare the meteor radar winds with thosefrom a medium-frequency partial reflection radar operating at 1.94
MHz. These three radars are located at Davis Station, Antarctica. We
then consider a middle-latitude 55 MHz meteor radar wind comparison
with a 1.98 MHz medium-frequency partial reflection radar todetermine how representative the Davis results are. At both sites, themedium-frequency radar winds are clearly underestimated, and theunderestimation increases from 80 km to the maximum height of 98
km. Correction factors are suggested for these results.

Keywords: Medium-frequency partial reflection radar, Meteor radar,
Davis station, Winds

Graphical abstract*Corresponding author: Iain M. Reid, ireid@atrad.com.au

FULL PAPER

Open Access

The Qujing incoherent scatter radar: system description
and preliminary measurements
ZongHua Ding*, Jian Wu, ZhengWen Xu, Bin Xu and LianDong Dai
Earth, Planets and Space 2018, 70, 87 DOI: 10.1186/s40623-018-0859-8
Received: 28 September 2017, Accepted: 15 May 2018, Published: 25 May 2018

Abstract
The Qujing incoherent scatter radar (QJISR), the first one in China with the geographic location (25.6°N, 103.8°E), was brought
into operation since the spring of 2014. The QJISR was a mono-static pulsed radar working in the operating frequency 500 MHz,the peak power 2 Megawatt, and a 29-m steerable parabolic dish. This paper mainly presents the basic configuration andimplementation of QJISR, including the antenna, transmitter, receiver, signal processing, and data analysis. Some preliminary
observation results are also reported including the raw echo, power spectra, and its ionospheric parameters: electron density,
electron temperature, ion temperature, and drift velocity.

Keywords: Incoherent scatter radar, Ionosphere,
Echo profile, Power spectra, Electron
density, Electron temperature, Ion
temperature

Fig. 2*Corresponding author: ZongHua Ding, zhdingmou@163.com
5Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017

FULL PAPER

Open Access

Statistical study about the influence of particle precipitation
on mesosphere summer echoes in polar latitudes during
July 2013
Abdur Rauf, Hailong Li*, Safi Ullah, Lin Meng, Bin Wang and Maoyan Wang
Earth, Planets and Space 2018, 70, 108 DOI: 10.1186/s40623-018-0885-6
Received: 20 February 2018, Accepted: 26 June 2018, Published: 3 July 2018

Abstract
Based on experimental observations with EISCAT VHF radar during the summer period, July 8–12, 2013, the observations of polarmesosphere summer echoes (PMSE) in the absence of particle precipitation indicate that particle precipitation is not a necessary
condition for PMSE to exist. But, particle precipitation still affects PMSE when they both occur simultaneously. So in this paper, therelationship between PMSE and particle precipitation both represented by average electron density, occurring simultaneously fortime interval of various lengths (t ≥ 2.56 min), is statisticallyanalyzed using the Spearman rank and Pearson linear correlation
coefficients. The new method by comparing the average electron
density at altitude of 90 km (proxy of particle precipitation) and
PMSE region at altitude of 80–90 km (proxy of PMSE) may compare
the two phenomena directly and give some relationship between
them. The percentage of events having positive values is dominant,which shows that the electron density variations due to theionization produced by energetic particle precipitations might havesome relationship with PMSE intensity. Moreover, the small
percentage of negative correlation coefficient observed might becaused by the very strong precipitation at that time.

Keywords: Ionosphere (particles precipitation), Meteorology andatmospheric dynamics (precipitation), PMSE, EISCATVHF radarFig. 1*Corresponding author: Hailong Li, Hailong703@163.com

FULL PAPER

Open Access

Tristatic observation of polar mesosphere winter echoes with
the EISCAT VHF radar on 8 January 2014: a case study
Evgenia Belova*, Maria Kawnine, Ingemar Häggström, Tima Sergienko, Sheila Kirkwood
and Anders Tjulin
Earth, Planets and Space 2018, 70, 110 DOI: 10.1186/s40623-018-0878-5
Received: 13 February 2018, Accepted: 19 June 2018, Published: 3 July 2018

Abstract
Polar mesosphere winter echoes (PMWE) were observed at 70 km over Tromsø, Norway, on 8 January 2014 using the tristatic
configuration of the European incoherent scatter VHF radar. For the interval 11:00–13:00 UT where the strongest patch of PMWE of about
6-min duration was detected, the spectra of the received signal were analysed for the Tromsø site and altitude profiles of spectral
parameters were derived. For the remote sites Kiruna and Sodankylä, the Doppler velocities and their vertical shear were determined byusing the measured autocorrelation functions. Ducted gravity waves with periods of 5–10 min were found in the vertical wind velocity
between 66 and 81 km altitudes. The duct might be formed around 70 and 77 km altitude where horizontal wind maxima were observedwith the Kiruna receiver. However, we did not find any close relation between wind shear at 70 km altitude and PMWE at the sameheight: the wind shear was present for 2 h, but
PMWE for only 6 min. Enhanced spectral width in thevertical Tromsø beam was observed for the PMWE
patch. We discussed these experimental findings inrelation to the winter echo generation mechanism.
Our conclusion is that the presence of patchy
negatively charged small-sized dust might explain
the observations although a gravity wave breaking
mechanism cannot be completely rejected.

Keywords: PMWE, EISCAT, Tristatic radarmeasurements, Mesospheric winds andwind shear, Ducted gravity waves

Graphical abstract*Corresponding author: Evgenia Belova, evgenia.belova@irf.se6

Earth, Planets and Space

FULL PAPER

Open Access

VHF radar measurements of momentum flux using
summer polar mesopause echoes
Iain M. Reid*, Rüdiger Rüster, Peter Czechowsky and Andrew J. Spargo
Earth, Planets and Space 2018, 70, 129 DOI: 10.1186/s40623-018-0902-9
Received: 27 February 2018, Accepted: 2 August 2018, Published: 10 August 2018

Abstract
We revisit previously unpublished analysis of observations of the dynamics of the mesopause region over the NorwegianIsland of Andøya (69°N, 16°E) made during a 1-week period in summer 1987 during the Middle Atmosphere CooperationSummer in Northern Europe (MAC-SINE) campaign using the mobile SOUSY VHF (53.5 MHz) Doppler radar operating in a
six-beam mode. We do this in the light of: (1) more recent developments in the measurement of the components of thedensity-normalized Reynolds stress tensor using meteor radars, and withmedium-frequency partial reflection radars using the hybrid Doppler
interferometric technique, and (2) satellite measurements of the absolute
upward flux of horizontal momentum. We consider of the density-normalized
total upward flux of horizontal momentum (u’w’+ v’w’) for the 83–90 km
height interval. Values of the component of the density-normalized flux forthe 6 min to 12.8 h period range, after the tidal components have been
removed, and the effects of the aspect sensitivity on the radar beam lookdirections have been accounted for vary between 5 m2 s−2 below 86 km and13 m2 s−2 above 86 km. The major contribution is from the 6 to 12.8 h period
range. The results of the analysis have implications for meteor radar estimatesof momentum flux and also for Doppler radar measurements of the same
term in the presence of aspect-sensitive scattering.

Keywords: Very high-frequency radar, Momentum flux, Polar mesospheresummer echoes

Graphical abstract*Corresponding author: Iain M. Reid, ireid@atrad.com.au

FULL PAPER

Open AccessOn the role of anisotropic MF/HF scattering inmesospheric wind estimation
Toralf Renkwitz*, Masaki Tsutsumi, Fazlul I. Laskar, Jorge L. Chau and Ralph Latteck
Earth, Planets and Space 2018, 70, 158 DOI: 10.1186/s40623-018-0927-0
Received: 16 March 2018, Accepted: 17 September 2018, Published: 1 October 2018

Abstract
The Saura radar is designed and used to measure winds and electron densities at polar latitudes (69°N) within the D region, namely
between 50 and 100 km altitude. A relatively narrow radar beam can be generated and steered into distinct pointing directions as arather large antenna array is used. From the observed radial velocities of the individual pointing directions, the horizontal and verticalwind fields can be obtained using the Doppler beam swinging (DBS) method. With recent upgrades to the radar, the interferometriccapabilities are largely improved allowing simultaneous application of different wind estimation techniques now, and also echo
localization. In recent studies, Saura DBS winds assuming isotropic scattering were found to be underestimated in comparison withhighly reliable winds observed with the MAARSY MST radar in the presence of polar mesospheric summer echoes (PMSE). This
underestimation has been investigated by analyzing the scattering positions as well as applying the imaging Doppler interferometry
technique. Besides this, Saura winds derived with the classical DBS method seem to be error prone at altitudes above 90 km and evenbelow this altitude for periods of enhanced ionization, e.g.,
particle precipitations. Various methods taking into
account the scattering positions have been used to correct
the wind underestimation. These winds are compared to
MST radar winds during PMSE, and an optimal combinationof these methods for the Saura radar is presented. This
combined wind data appears to be reliable; it shows
reasonable amplitudes as well as tidal structures for theentire altitude region.

Keywords: Radar, Wind estimation, D region,
Interferometry, Scattering

Graphical abstract*Corresponding author: Toralf Renkwitz, renkwitz@iap‑kborn.de7

Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017

FULL PAPER

Open Access

Atmospheric Kelvin–Helmholtz billows captured by
the MU radar, lidars and a fish-eye camera
Hubert Luce, Lakshmi Kantha, Masanori Yabuki and Hiroyuki Hashiguchi*
Earth, Planets and Space 2018, 70, 162 DOI: 10.1186/s40623-018-0935-0
Received: 20 November 2017, Accepted: 27 September 2018, Published: 3 October 2018

Abstract
On June 11, 2015, a train of large-amplitude Kelvin–Helmholtz (KH) billows was monitored by the Middle and Upper Atmosphere(MU) radar (Shigaraki MU Observatory, Japan) at the altitude of ~ 6.5 km. Four to five KH billows in formation and decay stages wereobserved for about 20 min at the height of a strong speed shear (> ~ 30 m s−1km−1), just a few hundred meters above a mid-levelcloud base. The turbulent billows had a spacing of about 3.5–4.0 km (3.71 km in average) and an aspect ratio (depth/spacing) of ~ 0.3.
The turbulence kinetic energy dissipation rate estimated was of the order of 10–50 mWkg−1, corresponding to moderate turbulenceaccording to ICAO (2010) classification. By chance, an upward-looking fish-eye camera producing pictures once every minutedetected smooth protuberances at the cloud base caused by the KH billows so that comparisons of their characteristics could bemade for the first time between the radar observations and thepictures. The main characteristics of the KH wave (horizontal
wavelength, phase front direction and phase speed) obtained fromthe analysis of the pictures were fully consistent with those foundfrom radar data. The pictures indicated that the billows wereadvected by the wind observed at the height of the critical level.
They also revealed a very small transverse extent (about twice thehorizontal spacing) suggesting that the large-amplitude KH billows
were generated by a very localized source. Micro-pulse lidar andRaman–Rayleigh–Mie lidar data also collected during the event
permitted us to confirm some of the characteristics of the billows.

Keywords: Kelvin–Helmholtz instability, Turbulence,

Kelvin–Helmholtz billows, Wind shear, Kinetic energy
dissipation rate, MU radar

Graphical abstract*Corresponding author: Hiroyuki Hashiguchi, hasiguti@rish.kyoto-u.ac.jp

FULL PAPER

Open Access

Stratospheric tropospheric wind profiling radars in
the Australian network
Bronwyn K. Dolman*, Iain M. Reid and Chris Tingwell
Earth, Planets and Space 2018, 70, 170 DOI: 10.1186/s40623-018-0944-z
Received: 22 March 2018, Accepted: 22 October 2018, Published: 29 October 2018

Abstract
The Australian Government Bureau of Meteorology completed the installation of a network of 9 new wind profiling radars acrossmainland Australia in 2017, which complement an existing network of 5 profilers and 5 research systems. This results in a networkof 14 operational, and 19 total, profilers across Australia and Davis Station in Antarctica. Four of the new profilers are higher
power stratospheric tropospheric systems, designed to measure winds
from near ground level to the tropopause, and maintain the upper air
network in Australia where sonde launches are no longer available.
Wind measurements in the near field of the radar are demonstrated
to be both possible and accurate by comparison with co-locatedradiosondes. Quality control procedures producing winds of sufficientaccuracy for presentation to forecasters and ingestion into global
numerical weather prediction models are described. The Australian
network data are available on the global telecommunications system
and are currently being ingested into all major models. First resultsfrom impact studies on forecast error reduction in the AustralianCommunity Climate and Earth Systems Simulator show remotestations have the greatest impact.

Keywords: Stratospheric tropospheric wind profilers, Wind
measurements, Forecast error impacts

Graphical abstract*Corresponding author: Bronwyn K. Dolman, bdolman@atrad.com.au
8Earth, Planets and Space

FULL PAPER

Open AccessOn a numerical model for extracting TKE dissipation ratefrom very high frequency (VHF) radar spectral width
Lakshmi Kantha, Hubert Luce and Hiroyuki Hashiguchi*
Earth, Planets and Space 2018, 70, 205 DOI: 10.1186/s40623-018-0957-7
Received: 26 June 2018, Accepted: 13 November 2018, Published: 24 December 2018

Abstract
The standard model (e.g., Hocking in Earth Planets Space 51:525–541, 1999), ε = c0σ2N, (where σ is the radar spectral width assumed to be equal to vertical turbulence velocity
fluctuation √w 2 , N is the buoyancy frequency, and c0 is a constant), derived from Weinstock (J Atmos Sci 35:1022–1027, 1978; J Atmos Sci 38:880–883, 1981) formulation, hasbeen used extensively for estimating the turbulence kinetic energy (TKE) dissipation rate ε under stable stratification from VHF radar Doppler spectral width σ. The Weinstock
model can be derived by simply integrating the TKE spectrum in the wavenumber space from the buoyancy wavenumber kB = Nσ to ∞. However, it ignores the radar volume
dimensions and hence its spatial weighting characteristics. Labitt (Some basic relations concerning the radar measurements of air turbulence, MIT Lincoln Laboratory, ATC
Working Paper NO 46WP-5001, 1979) and White et al. (J Atmos Ocean Technol 16:1967–1972, 1999) formulations do take into account the radar spatial weighting characteristics,
but assume that the wavenumber range in the integration of TKE spectrum extends from 0 to ∞. The White et al. model accounts for wind speed effects, whereas the other two
do not. More importantly, all three formulations make the assumption that k−5/3 spectral shape of TKE spectrum extends across the entire wavenumber range of integration. It is
traditional to use Weinstock formulation for k B−1 < 2a, 2b (where a and b are radar volume dimensions in the horizontal and vertical directions) and White et al. formulation(without wind advection) for k B−1 > 2a, 2b. However, there is no need to invoke these asymptotic limits. We present
here a numerical model, which is valid for all values of buoyancy wavenumber kB and transitions from ε ~ σ2behavior at lower values of σ in accordance with Weinstock’s model, to ε ~ σ3 at higher values of σ, in agreementwith Chen (J Atmos Sci 31:2222–2225, 1974) and Bertin et al. (Radio Sci 32:791–804, 1997). It can also account for
the effects of wind speed, as well the beam width and altitude. Following Hocking (J Atmos Terr Phys 48:655–670,
1986, Earth Planets Space 51:525–541, 1999), the model also takes into account contributions of velocity
fluctuations beyond the inertial subrange. The model has universal applicability and can also be applied toconvective turbulence in the atmospheric column. It can also be used to explore the parameter space and hence
the influence of various parameters and assumptions on the extracted ε values. In this note, we demonstrate theutility of the numerical model and make available a MATLAB code of the model for potential use by the radar
community. The model results are also compared against in situ turbulence measurements using an unmanned
aerial vehicle (UAV) flown in the vicinity of the MU radar in Shigaraki, Japan, during the ShUREX 2016 campaign.

Keywords: VHF radar, MU radar, Unmanned aerial vehicles (UAV), Turbulence kinetic energy(TKE), TKE dissipation rate, Radar model, Stably stratified flows, Inertial subrange,
Buoyancy subrange, Viscous subrange, Troposphere, Buoyancy scale, Ozmidov
scale, Viscous scale, Convective turbulence, Convection, Numerical model

Graphical abstract*Corresponding author: Hiroyuki Hashiguchi, hasiguti@rish.kyoto-u.ac.jp

FULL PAPER

Open Access

Turbulence kinetic energy dissipation rates estimatedfrom concurrent UAV and MU radar measurements
Hubert Luce, Lakshmi Kantha, Hiroyuki Hashiguchi*, Dale Lawrence and Abhiram Doddi
Earth, Planets and Space 2018, 70, 207 DOI: 10.1186/s40623-018-0979-1
Received: 28 June 2018, Accepted: 15 December 2018, Published: 27 December 2018

Abstract
We tested models commonly used for estimating turbulence kinetic energy dissipation rates ε from very high frequency stratosphere–troposphereradar data. These models relate the root-mean-square value σ of radial velocity fluctuations assessed from radar Doppler spectra to ε. For thispurpose, we used data collected from the middle and upper atmosphere (MU) radar during the Shigaraki unmanned aerial vehicle (UAV)—radar
experiment campaigns carried out at the Shigaraki MU Observatory, Japan, in June 2016 and 2017. On these occasions, UAVs equipped with fastresponse and low-noise Pitot tube sensors for turbulence measurements were operated in the immediate vicinity of the MU radar. Radar-derived
dissipation rates ε estimated from the various models at a range resolution of 150 m from the altitude of 1.345 km up to the altitude of ~ 4.0 km, a(half width half power) beam aperture of 1.32° and a time resolution of 24.6 s, were compared to dissipation rates (εU) directly obtained from relative
wind speed spectra inferred from UAV measurements. Firstly, statistical analysis results revealed a very close relationship between enhancements of−5 2 −3σ and εU for εU>~10 m s , indicating that both instruments detected the same turbulent events with εU above this threshold. Secondly, εU was foundto be statistically proportional to σ3, whereas a σ2 dependence is expected when the size of the largest turbulent eddies is smaller than thelongitudinal and transverse dimensions of the radar sampling volume.
The σ3 dependence was found even after excluding convectively
generated turbulence in the planetary boundary layer and below
clouds. The best agreement between εU and radar-derived ε was
obtained with the simple formulation based on dimensional analysis
ε = σ3/Lc where LC ≈ 50–70 m. This empirical expression constitutes asimple way to estimate dissipation rates in the lower tropospherefrom MU radar data whatever the sources of turbulence be, in clear air
or cloudy conditions, consistent with UAV estimates.

Keywords: VHF radar, Unmanned aerial vehicle, Atmosphericturbulence, Energy dissipation rate, Outer scales ofturbulence, Doppler variance

Graphical abstract*Corresponding author: Hiroyuki Hashiguchi, hasiguti@rish.kyoto-u.ac.jp
9Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and EISCAT18 Meetings, May 2017

EXPRESS LETTER

Open Access

Spatial distribution of errors associated with multistatic
meteor radar
W. K. Hocking
Earth, Planets and Space 2018, 70, 93 DOI: 10.1186/s40623-018-0860-2
Received: 28 February 2018, Accepted: 15 May 2018, Published: 5 June 2018

Abstract
With the recent increase in numbers of small and versatile low-power meteor radars, the opportunity exists to benefit fromsimultaneous application of multiple systems spaced by only a few hundred km and less. Transmissions from one site can berecorded at adjacent receiving sites using various degrees of forward scatter, potentially allowing atmospheric conditions in
the mesopause regions between stations to be diagnosed. This can allow
a better spatial overview of the atmospheric conditions at any time. Suchstudies have been carried out using a small version of such so-called
multistatic meteor radars, e.g. Chau et al. (Radio Sci 52:811–828, 2017,https://doi.org/10.1002/2016rs006225). These authors were able to also
make measurements of vorticity and divergence. However, measurement
uncertainties arise which need to be considered in any application ofsuch techniques. Some errors are so severe that they prohibit useful
application of the technique in certain locations, particularly for zones at
the midpoints of the radars sites. In this paper, software is developed toallow these errors to be determined, and examples of typical errors
involved are discussed. The software should be of value to others whowish to optimize their own MMR systems.

Keywords: Radar, Meteor, Errors, Multistatic, Specular, Reflection, Scatter
Graphical abstract

Corresponding author: W. K. Hocking, whocking@uwo.ca

TECHNICAL REPORT

Open Access

Survey of conditions for artificial aurora experiments at
EISCAT Tromsø using dynasonde data
T. T. Tsuda*, M. T. Rietveld, M. J. Kosch, S. Oyama, K. Hosokawa, S. Nozawa, T. Kawabata,A. Mizuno and Y. Ogawa
Earth, Planets and Space 2018, 70, 40 DOI: 10.1186/s40623-018-0805-9
Received: 5 November 2017, Accepted: 14 February 2018, Published: 8 March 2018

Abstract
We report a brief survey on conditions for artificial aurora optical experiments in F region heating with O-mode at the EISCAT
Tromsø site using dynasonde data from 2000 to 2017. The results obtained in our survey indicate the following: The possible
conditions for conducting artificial aurora experiments are concentrated in twilight hours in both evening and morning,
compared with late-night hours; the possible conditions appear in fall, winter, and spring, while there is no chance in summer,
and the month-to-month variation among fall, winter, and springis not clear. The year-to-year variation is well correlated with thesolar cycle, and experiments during the solar minimum would bealmost hopeless. These findings are useful for planning future
artificial aurora optical experiments.

Keywords: Artificial aurora, Ionospheric heating, EISCAT, Tromsø,
Dynasonde

Graphical abstract*Corresponding author: T. T. Tsuda, takuo.tsuda@uec.ac.jp
10Earth, Planets and SpaceTECHNICAL REPORT

Open Access

Survey of conditions for artificial aurora experiments by
the second electron gyro-harmonic at EISCAT Tromsø
using dynasonde data
T. T. Tsuda*, M. T. Rietveld, M. J. Kosch, S. Oyama, Y. Ogawa, K. Hosokawa, S. Nozawa,T. Kawabata and A. Mizuno
Earth, Planets and Space 2018, 70, 94 DOI: 10.1186/s40623-018-0864-y
Received: 26 February 2018, Accepted: 16 May 2018, Published: 6 June 2018

Abstract
We report a brief survey of matching conditions for artificial aurora optical experiments utilizing the second electron gyro-harmonic(2.7-MHz frequency) in F region heating with O-mode at the EISCAT Tromsø site using dynasonde data from 2000 to 2017. Our survey
indicates the following: The possible conditions for successful artificial aurora experiments are concentrated on twilight hours in bothevening and morning, compared with late night hours; the possible
conditions appear in fall, winter, and spring, while there is no chancein summer, and the month-to-month variation among fall, winter,and spring is not so clear; the year-to-year variation is well correlated§with the solar activity. These characteristics in the case of 2.7-MHz
frequency are basically similar to those previously reported in thecase of 4-MHz frequency. However, the number of days meeting the
゜possible condition in the case of 2.7-MHz frequency is obviously
large, compared with that in the case of 4-MHz frequency. In
particular, unlike the 4-MHz frequency operation, the 2.7-MHz＼＼
frequency operation can provide many chances for successful
／＼
凸
\- ヽ
ノ←
artificial aurora experiments even during the solar minimum.
ヽ
／
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300

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100

2000200120022003200420052006 2007 2008 2009 2010201120122013201420152016 2017
year

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Keywords: Artificial aurora, Ionospheric heating, Second electron
gyro-harmonic, EISCAT, Tromsø, Dynasondeso一

2000200120022003200420052006 2007 2008 2009 2010201120122013201420152016 2017year

Graphical abstract*Corresponding author: T. T. Tsuda, takuo.tsuda@uec.ac.jp

11

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Contents
Special issue “Recent Advances in MST and EISCAT/Ionospheric Studies – Special Issue of the Joint MST15 and
EISCAT18 Meetings, May 2017” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mamoru Yamamoto, Wayne K. Hocking, Satonori Nozawa,
Juha Vierinen, Huixin Liu and Nozomu Nishitani

1

Imaging high-latitude plasma density irregularities resulting from particle precipitation: spaceborne L-band SAR and
EISCAT observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hiroatsu Sato, Jun Su Kim, Norbert Jakowski and Ingemar Häggström 4Characterization of atmospheric structures observed by a VHF MST-type radar in the troposphere over Santa Cruz,
Costa Rica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Marcial Garbanzo-Salas and Wayne Hocking 4
Mesospheric radar wind comparisons at high and middle southern latitudes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Iain M. Reid, Daniel L. McIntosh, Damian J. Murphy and Robert A. Vincent 5
The Qujing incoherent scatter radar: system description and preliminary measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ZongHua Ding, Jian Wu, ZhengWen Xu, Bin Xu and LianDong Dai 5
Statistical study about the influence of particle precipitation on mesosphere summer echoes in polar latitudes
during July 2013 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Abdur Rauf, Hailong Li, Safi Ullah, Lin Meng, Bin Wang and Maoyan Wang 6
Tristatic observation of polar mesosphere winter echoes with the EISCAT VHF radar on 8 January 2014: a case study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evgenia Belova, Maria Kawnine, Ingemar Häggström, Tima Sergienko, Sheila Kirkwood and Anders Tjulin 6
VHF radar measurements of momentum flux using summer polar mesopause echoes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Iain M. Reid, Rüdiger Rüster, Peter Czechowsky and Andrew J. Spargo 7
On the role of anisotropic MF/HF scattering in mesospheric wind estimation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Toralf Renkwitz, Masaki Tsutsumi, Fazlul I. Laskar, Jorge L. Chau and Ralph Latteck 7
Atmospheric Kelvin–Helmholtz billows captured by the MU radar, lidars and a fish-eye camera. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hubert Luce, Lakshmi Kantha, Masanori Yabuki and Hiroyuki Hashiguchi 8
Stratospheric tropospheric wind profiling radars in the Australian network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bronwyn K. Dolman, Iain M. Reid and Chris Tingwell 8
On a numerical model for extracting TKE dissipation rate from very high frequency (VHF) radar spectral width. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lakshmi Kantha, Hubert Luce and Hiroyuki Hashiguchi 9
Turbulence kinetic energy dissipation rates estimated from concurrent UAV and MU radar measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hubert Luce, Lakshmi Kantha, Hiroyuki Hashiguchi, Dale Lawrence and Abhiram Doddi 9
Spatial distribution of errors associated with multistatic meteor radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W. K. Hocking 10
Survey of conditions for artificial aurora experiments at EISCAT Tromsø using dynasonde data
. . . . . . . . . . . . . . . . . . . . . . . . . . . . T. T. Tsuda, M. T. Rietveld, M. J. Kosch, S. Oyama, K. Hosokawa, S. Nozawa, T. Kawabata, A. Mizuno and Y. Ogawa 10
Survey of conditions for artificial aurora experiments by the second electron gyro-harmonic at EISCAT Tromsø
using dynasonde data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. T. Tsuda, M. T. Rietveld, M. J. Kosch, S. Oyama, Y. Ogawa, K. Hosokawa,
S. Nozawa, T. Kawabata and A. Mizuno

11

Cover image: (Upper-right) Research Institute for Sustainable Humanosphere, Kyoto University(Bottom) National Institute of Polar Research